Nice drivers!
Thanks for sharing your experiments. This is going to be very interesting.
I wonder if its worth taking a modular approach with your design so each driver can have its own baffle and box? The idea is to make an OB baffle that can also be used as the front panel of the box to save work. Then with each driver separate you can easily mix and match drivers.
Would you try the Scanspeak 10" woofer as an OB with the Alpair 5.3 as an experiment for a stero pair of desktop speakers? Ive an idea it could sound pretty good. Good bass as a foundation seems to totally change the perceived sound from the upper drivers. Obviously its doesnt change the measured sound out of the upper drivers but perception isnt linear.
Thanks for sharing your experiments. This is going to be very interesting.
I wonder if its worth taking a modular approach with your design so each driver can have its own baffle and box? The idea is to make an OB baffle that can also be used as the front panel of the box to save work. Then with each driver separate you can easily mix and match drivers.
Would you try the Scanspeak 10" woofer as an OB with the Alpair 5.3 as an experiment for a stero pair of desktop speakers? Ive an idea it could sound pretty good. Good bass as a foundation seems to totally change the perceived sound from the upper drivers. Obviously its doesnt change the measured sound out of the upper drivers but perception isnt linear.
Yes, it is likely that i shall try the 10" drivers in a SLOB configuration, and if so they'll definitely be tested paired-up with the little alpairs, too. I've never really thought of OB as the obvious choice for bass, but I am still quite intrigued by the slot-loading approach so will probably have a go as the testing progresses.
Though I'll only be doing modest testing as needed to inform my own design choices; I'm unlikely to conduct robust experiments or generate results that would necessarily be applicable to other situations and conditions.
Though I'll only be doing modest testing as needed to inform my own design choices; I'm unlikely to conduct robust experiments or generate results that would necessarily be applicable to other situations and conditions.
You have a wonderful array of drivers for your experiments. I can see you are going to have lots of fun. Do you have a measurement mic to help?
With the OB bass nearfield experiments you might find you can get OK SPL over 40Hz where you listen with SPL that drops off rapidly with distance and doesn't vibrate the walls, allowing peace with the neighbour. Especially if the desk is away from the common wall and the drivers are near 90degrees.
With the Scanspeak 10" you have two OB bass choices.
One is a stereo pair in a plain baffle or U baffle. One left one right. With the full range above it. If you are making a sealed box for the 10" its no more work experimenting with a plain OB (just the front panel) or a U-baffle (the box with the rear pane off).
The other option for the 10" is single mono ripole. That will get the frequency reach down. But upper reach is limited. It might go well for 40Hz-100Hz as a bass fill in to back up the 4"? The problem with a desktop system is where to put a single ripole? Do you have desk space to put a ripole near field on the desk?
With the OB bass nearfield experiments you might find you can get OK SPL over 40Hz where you listen with SPL that drops off rapidly with distance and doesn't vibrate the walls, allowing peace with the neighbour. Especially if the desk is away from the common wall and the drivers are near 90degrees.
With the Scanspeak 10" you have two OB bass choices.
One is a stereo pair in a plain baffle or U baffle. One left one right. With the full range above it. If you are making a sealed box for the 10" its no more work experimenting with a plain OB (just the front panel) or a U-baffle (the box with the rear pane off).
The other option for the 10" is single mono ripole. That will get the frequency reach down. But upper reach is limited. It might go well for 40Hz-100Hz as a bass fill in to back up the 4"? The problem with a desktop system is where to put a single ripole? Do you have desk space to put a ripole near field on the desk?
That's a good question. What are your thoughts?
It looks like Kev is going to find out for himself about dipole but possible advantages for Kev are
1. deeper sound stage imaging
2. less bass leakage
3. fun experimenting
First thoughts were that there won't be much difference if this is a close listening situation with no significant walls. (I assume that equalising the dipole is no problem but it is a consideration nonetheless).
If the desk is up against a wall then this will change. Deeper soundstage implies that this all needs to involve the room, which requires planning.. keeping in mind that this proposal doesn't necessarily improve imaging, but spaciousness.
I'm not sure I understand the bass leakage thing but I agree it will be fun experimenting.
If the desk is up against a wall then this will change. Deeper soundstage implies that this all needs to involve the room, which requires planning.. keeping in mind that this proposal doesn't necessarily improve imaging, but spaciousness.
I'm not sure I understand the bass leakage thing but I agree it will be fun experimenting.
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Good point. Something more for Kev to experiment with.
Kev, you better put some wheels on the desk.
Its all good fun till the neighbour gets woken up with bass leaking over ...
Yes, Open Baffles have been suggested a number of times during the thread, and they seem to have some potentially useful characteristics so will undoubtedly see some testing as i progress. Though either way I've (intentionally) no preference for them or any other methods at this stage.
Very close listening will already make room effects much less of an issue for me the listener, and as regards leakage the SPL requirements will be reduced throughout (rather than mostly just to the sides). More conventional boxes can be quite directional at frequencies above several hundred herts or more in any case, and don't suffer the rear projection (which would make room placement more difficult when layout options are limited).
Not that the two couldn't be combined. But where I think OBs 'might' bring unique (or at least unusual) benefit to this project is in the lower frequencies. Where many other methods would radiate in all directions an OB might allow some control over what SPL directly reaches the party-wall, and to some extent what might be reflected to it. Though in practice it would need to achieve the figure-eight dispersion pattern at low frequencies and (given my inflexible space) I'd want to lose/absorb the rear lobe somehow, which is going to be challenging at low frequencies. So not a foregone conclusion, at this stage.
Very close listening will already make room effects much less of an issue for me the listener, and as regards leakage the SPL requirements will be reduced throughout (rather than mostly just to the sides). More conventional boxes can be quite directional at frequencies above several hundred herts or more in any case, and don't suffer the rear projection (which would make room placement more difficult when layout options are limited).
Not that the two couldn't be combined. But where I think OBs 'might' bring unique (or at least unusual) benefit to this project is in the lower frequencies. Where many other methods would radiate in all directions an OB might allow some control over what SPL directly reaches the party-wall, and to some extent what might be reflected to it. Though in practice it would need to achieve the figure-eight dispersion pattern at low frequencies and (given my inflexible space) I'd want to lose/absorb the rear lobe somehow, which is going to be challenging at low frequencies. So not a foregone conclusion, at this stage.
This is what the smarter guys say about nearfield OB sub: https://www.diyaudio.com/community/threads/slob-2x12-subwoofer-for-near-field.384529/post-6980792
If I understand it correctly, in nearfield, you get no bass cancellation, but your neighbors in far field do. Mine is just being built.
If I understand it correctly, in nearfield, you get no bass cancellation, but your neighbors in far field do. Mine is just being built.
Thank you, that is an interesting thread with some other interesting links given, too. I shall be keen to see how your project goes; the best of luck with it!
In my situation, not sure how convenient it might (not) be to position a central vertical slot up close enough for this to work optimally. The obvious answer would be to cross over low enough that other positions could be used without the location being (very) audible. Though as I'm avoiding very low frequencies, a low crossover would leave the sub providing only a small frequency range for all that extra hardware. So perhaps another option might be two smaller and slightly higher-range SLOBs positioned left and right in some way.
In my situation, not sure how convenient it might (not) be to position a central vertical slot up close enough for this to work optimally. The obvious answer would be to cross over low enough that other positions could be used without the location being (very) audible. Though as I'm avoiding very low frequencies, a low crossover would leave the sub providing only a small frequency range for all that extra hardware. So perhaps another option might be two smaller and slightly higher-range SLOBs positioned left and right in some way.
I've been doing some preliminary tests with the little alpair 5.3 and am pleased so far. To my ears it doesn't seem bad at all for the higher frequencies so I'll be happy to live with it instead of a tweeter, maybe with some correction or shaping of the response. It is surprisingly good lower down too. Though that is 'for its size'; I'm forming the opinion that I'd not want to use it down to the kind of frequencies that would cross over nicely to a subwoofer (irrespective of the sub design) - certainly not without the alpair seeing big enclosures/baffles or DSP, none of which are very appealing given the nature of the project and the driver's modest displacement. IMO something like 300Hz (give or take) could be the lowest I'd want to cross it over; maybe higher.
So, in terms of this project if i went with the little alpairs I would also want to use them with the scanspeak midwoofers in a WAW configuration, which was what I expected really. Having done some simulations and tests the results of that are very encouraging, the pairing will reach down to 40hz (-6dB) at 93dB which is more than enough for me when sat very close. I wouldn't want lower or louder under these circumstances, so in that configuration the big 10" woofers aren't particularly needed.
Though there might instead be some mileage in using a bigger wide-range that could reach down to say 80hz unaided with decent umph; basically a full-range-satellite + sub setup. I'm less keen on that configuration in concept, but for practical reasons it could be appealing if it allowed a particularly small enclosure (for the closely positioned hardware), if the bigger full-range didn't suffer too much at the high frequencies, and if the separate location of the bigger bass drivers were genuinely (audibly) undetectable.
So, in terms of this project if i went with the little alpairs I would also want to use them with the scanspeak midwoofers in a WAW configuration, which was what I expected really. Having done some simulations and tests the results of that are very encouraging, the pairing will reach down to 40hz (-6dB) at 93dB which is more than enough for me when sat very close. I wouldn't want lower or louder under these circumstances, so in that configuration the big 10" woofers aren't particularly needed.
Though there might instead be some mileage in using a bigger wide-range that could reach down to say 80hz unaided with decent umph; basically a full-range-satellite + sub setup. I'm less keen on that configuration in concept, but for practical reasons it could be appealing if it allowed a particularly small enclosure (for the closely positioned hardware), if the bigger full-range didn't suffer too much at the high frequencies, and if the separate location of the bigger bass drivers were genuinely (audibly) undetectable.
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This afternoon has seen more initial/basic testing just to get a feel for things, and also more thought and research about implications other than frequency range alone - e.g. such as distortion, excursion and spl.
As a result, I'm starting to see (wrt this project) the little alpairs would best be employed just as wide-range tweeters in order to cross-over at less than 1/4wavelength of the driver spacing (which in this case would be around 660hz) - rather than trying to make them as full-range as humanly possible. This would also make better use of the scanspeak 15Ws and so overall seem a better way to pair them together.
The other main contender is still the full-range approach, which still seems quite advantageous for very close listening. Though (not unexpectedly) I'd definitely prefer bigger FR drivers to achieve that; perhaps the alpair 10.3 might work well in a small enclosure or baffle of some kind. Possibly supported either by a modest subwoofer or in a low-crossed WAW configuration - 1/4 wavelength below (say) 150hz is large enough to allow quite some flexibility in where such woofers might be placed.
As a result, I'm starting to see (wrt this project) the little alpairs would best be employed just as wide-range tweeters in order to cross-over at less than 1/4wavelength of the driver spacing (which in this case would be around 660hz) - rather than trying to make them as full-range as humanly possible. This would also make better use of the scanspeak 15Ws and so overall seem a better way to pair them together.
The other main contender is still the full-range approach, which still seems quite advantageous for very close listening. Though (not unexpectedly) I'd definitely prefer bigger FR drivers to achieve that; perhaps the alpair 10.3 might work well in a small enclosure or baffle of some kind. Possibly supported either by a modest subwoofer or in a low-crossed WAW configuration - 1/4 wavelength below (say) 150hz is large enough to allow quite some flexibility in where such woofers might be placed.
Yes, on reflection that is quite probable; good call, thank you!
Probably i could get away with quite a lot more; this is a new world and so it goes slightly against the grain, but further testing could easily and quickly banish my prejudices in that respect. The tweeter/midtweeter-to-midbass distance is a fairly simple situation, and not even an issue if I went with a bigger full-range driver instead, but it would be particularly good to do some tests to find what flexibility there is for placement and frequency of the bass drivers.
As things progress, I'm starting to think that (physically) unobtrusive bass in the relative nearfield is going to be one of the bigger areas for testing. Even though I won't be permitted to produce loads of it (or maybe even because of that) it is going to be quite important.
Probably i could get away with quite a lot more; this is a new world and so it goes slightly against the grain, but further testing could easily and quickly banish my prejudices in that respect. The tweeter/midtweeter-to-midbass distance is a fairly simple situation, and not even an issue if I went with a bigger full-range driver instead, but it would be particularly good to do some tests to find what flexibility there is for placement and frequency of the bass drivers.
As things progress, I'm starting to think that (physically) unobtrusive bass in the relative nearfield is going to be one of the bigger areas for testing. Even though I won't be permitted to produce loads of it (or maybe even because of that) it is going to be quite important.
I've now established that the WAW combo of alpair-5.3 and scanspeak-15w/8530k01 will work for me very well indeed as a pair of small speakers. But.. they're perhaps not as focused as they might be on what i want in this particular case: the sizes and volumes involved are a little bigger than I'd ideally like for very close positioning, and in fact the approach is perhaps excessive generally. The modest SPL and on-axis listening (that i have in mind) might allow a more compact and elegant answer.
So, I've decided to try bigger full-range drivers than the alpair 5.3 in order to use them full-range, and also in overall smaller enclosures (or baffles) than the WAW combo mentioned above. Specifically, I've a couple of alpair 11MS drivers on the way; I'll need to work a few days of extra overtime to pay for them but they could do exactly what I'm looking for, and might ultimately cost less than the multi-way, multi-amped setup I'd envisaged.
So, I've decided to try bigger full-range drivers than the alpair 5.3 in order to use them full-range, and also in overall smaller enclosures (or baffles) than the WAW combo mentioned above. Specifically, I've a couple of alpair 11MS drivers on the way; I'll need to work a few days of extra overtime to pay for them but they could do exactly what I'm looking for, and might ultimately cost less than the multi-way, multi-amped setup I'd envisaged.
I've also been testing some open baffles. They work (of course) but all things considered, I don't think they are entirely what I'm looking for wrt 'very' close listening. I'd want them larger than is really ideal, to avoid being crossed higher than I'd like to a sub, or else would need more eq than I'd like to put into full-range drivers.
However, for slightly less close listening they still have lots of potential. They probably also offer more that is beneficial at slightly larger distances and higher SPLs, so that may be their sweet spot.
As this progresses, I think there may indeed be a case for having a second pair of speakers, to play to the small room when circumstances allow. If so they'll likely be two-ways using my existing drivers, and I shall revisit open baffles again, for them.
However, for slightly less close listening they still have lots of potential. They probably also offer more that is beneficial at slightly larger distances and higher SPLs, so that may be their sweet spot.
As this progresses, I think there may indeed be a case for having a second pair of speakers, to play to the small room when circumstances allow. If so they'll likely be two-ways using my existing drivers, and I shall revisit open baffles again, for them.
The alpair 11ms drivers arrived. The first physical impression is that the surround makes quite a large diameter for the actual cone/sd size, which is unfortunate in this application but was expected and is acceptable. On the plus side, it is also fairly large in the magnet department, which bodes well. The cone-shape is pretty shallow, and indeed the whole driver isn't all that deep.
I put one in an existing sealed cabinet just to get a feel for its behaviour (the cabinet is 9Litres, which is about right). The low end is pretty frugal compared to similarly sized sealed 2-ways that I'm used to. However it is there, so it is very likely that some EQ can fix that; there is decent excursion. I'm only wanting low SPLs, and not chasing bass frequencies that would annoy next-door. There may even be scope to reduce the cabinet size and possibly use a linkwitz-transform.
More importantly the high end seems fine; I was concerned that a (relatively) large driver might mean excessively small listening angle or sluggishness. Also, I can get closer to these than my 2-ways with it still sounding coherent and 'normal', in fact (within reason) better and better. So overall I think the 11MS drivers are worth pursuing a proper design for. I'll probably start a new thread in the full-range forum, now that this is the direction to be taken.
I put one in an existing sealed cabinet just to get a feel for its behaviour (the cabinet is 9Litres, which is about right). The low end is pretty frugal compared to similarly sized sealed 2-ways that I'm used to. However it is there, so it is very likely that some EQ can fix that; there is decent excursion. I'm only wanting low SPLs, and not chasing bass frequencies that would annoy next-door. There may even be scope to reduce the cabinet size and possibly use a linkwitz-transform.
More importantly the high end seems fine; I was concerned that a (relatively) large driver might mean excessively small listening angle or sluggishness. Also, I can get closer to these than my 2-ways with it still sounding coherent and 'normal', in fact (within reason) better and better. So overall I think the 11MS drivers are worth pursuing a proper design for. I'll probably start a new thread in the full-range forum, now that this is the direction to be taken.